The astronomers saw a pulse of X-rays that rose and fell in intensity every 200 seconds. The team thinks that the oscillation is coming from the last bits of the star, which are making their final orbits before being sucked into the hole. They reported their results in Science.

This result may open the possibility of probing general relativity beyond our local Universe. Work based on Einstein’s general theory of relativity stipulates that there is a minimum distance at which material can stably orbit a black hole before it is swallowed.

The team’s calculations suggest that the star’s remains were probably just one million kilometers from the event horizon — the surface beyond which nothing, not even light, can escape a black hole’s clutches.